This proposed two year study provides an experimental design which has the potential for investigating the interaction between age and other fall risk factors such as surface condition and firmness, lighting, peripheral vision, and workload. In the proposed study, postural instability and fall potential of above-mentioned fall risk factors of 100 industrial workers will be evaluated in 32 tests simulating various combinations of these risk factors while performing simulated tasks which might occur in an industrial environment. Subjects ranging in age from 21 years to 55 years will be tested immediately after exposure to light and moderate-to-heavy workloads to quantitate their postural stability while standing on surfaces with different contamination conditions and firmness, peripheral vision (blocked and unblocked), and environmental lighting conditions. Each subject will undergo 32 tests consisting of each of 32 possible treatment combinations among four risk factor conditions and two workloads. Condition 1 will be standing on dry or oily surface. Condition 2 will be "acceptable, good" or "unacceptable, poor" environmental lighting. Condition 3 will be blocked or unblocked peripheral vision, and Condition 4 will be standing on firm or compliant surface. All subjects will also be tested for the measurement of Estimated Maximum Displacement of Center of Pressure (EMAXDCP). The results of this test will provide an estimation of subject's "Functional Stability Boundary" and the calculation of Index of Proximity to Stability Boundary (IPSB). The value of IPSB obtained during the postural stability tests will be used to determine which of the test conditions (out of 32 tests) pushed the body's center of pressure (CP) to or beyond its stability boundary and, therefore, had the potential to create an accident due to a fall. Before and immediately after completion of a workload, the subject will be tested for upright postural sway and postural corrective responses to a number of simulated tasks which might occur in an industrial environment. Postural sway parameters will be measured to investigate the age-associated differences in maintenance of upright postural balance under all combinations of workloads and four risk factor conditions. The results obtained from 32 tests will be rank ordered for fall potential using various criteria. Based on results of the present study, future studies with a larger worker population are planned to develop intervention strategies for fall prevention.